Rat DNA points to Pacific migrations.Archaeologists regard members of the ancient, seafaring Lapita culture Lapita culture Cultural complex of what were presumably the original human settlers of Melanesia, much of Polynesia, and parts of Micronesia. The Lapita people were originally from New Guinea or some other region of Austronesia. as the ancestors of Polynesians, who now live on a large group of western Pacific islands collectively known as Oceania. Where the Lapita originally came from and the way in which they occupied a string of islands that spans more than 2,000 miles remains a topic of hot debate. A new genetic analysis of Pacific rats, which canoe-traveling Lapita colonists brought with them for food and introduced to Oceania, adds weight to an earlier theory that Lapita mariners based in Southeast Asia Southeast Asia, region of Asia (1990 est. pop. 442,500,000), c.1,740,000 sq mi (4,506,600 sq km), bounded roughly by the Indian subcontinent on the west, China on the north, and the Pacific Ocean on the east. moved across the region in a series of migrations, from 6,000 to 3,000 years ago. Elizabeth Matisoo Smith and Judith H. Robins, both of the University of Auckland Not to be confused with Auckland University of Technology. The University of Auckland (Māori: Te Whare Wānanga o Tāmaki Makaurau) is New Zealand's largest university. in New Zealand New Zealand (zē`lənd), island country (2005 est. pop. 4,035,000), 104,454 sq mi (270,534 sq km), in the S Pacific Ocean, over 1,000 mi (1,600 km) SE of Australia. The capital is Wellington; the largest city and leading port is Auckland. , obtained mitochondrial DNA Mitochondrial DNA (mtDNA) is the DNA located in organelles called mitochondria. Most other DNA present in eukaryotic organisms is found in the cell nucleus. Nuclear and mitochondrial DNA are thought to be of separate evolutionary origin, with the mtDNA being derived from the from more than l00 Pacific rats. These genetic samples bad been extracted either from bones found at Lapita archaeological sites or from the remains of recently deceased animals throughout Oceania. A mutation-rich stretch of the rats' mitochondrial DNA exhibits three geographically distinct nucleotide-sequence patterns, the investigators report in the June 15 Proceedings of the National Academy of Sciences The Proceedings of the National Academy of Sciences of the United States of America, usually referred to as PNAS, is the official journal of the United States National Academy of Sciences. . One pattern appears only on islands just off the Asian coast, reflecting interaction among people who probably didn't migrate elsewhere, Matisoo-Smith and Robins propose. A second pattern extends from the same islands into Oceania's western half, apparently mirroring human migration along that path. A third pattern appears on one western island, Halmahera, and on several of Oceania's easternmost islands, possibly marking a separate Lapita dispersal. |
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